Switch for district-telephone lines



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A. MTEANKENBEEG.

SWITCH EOE DISTRICT TELEPHONE LINE-s.

Patented Aug. 30,1881.

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SWITCH FOR DISTRICT TELEPHONE LINES. No. 246,305; Patented Aug. 30,1881.

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A. M. FRANKENBERG. SWITCH FOR DISTRICT TELEPHONE LINES.

No. 246,305. Patented Aug. 30,1881.

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. ble ground-connection in combination with an the line of section beingtaken through the .other Telephone Lines; and I do hereby dewhich form apartof this specification.

. operator in charge. Among other objects and ephonic communicationswith any subscriber UNrTn STATES ANTHONY M. FBANKENBER-G, OF BALTIMORE,MARYLAND.

PATIENT OFFICE.

SWITCH FOR DISTRICT-TELEPHONE LINES SPECIFICATION forming part ofLetters Patent No. 246,305, dated August 30, 1881.

Application filed November 6, 1880. (Model) To all whom it may concernBe it known that l, ANTHONY M. FRANK- ENBERG, of Baltimore city,in theState ofMaryland, have invented certain new and useful Improvements inSwitches for District and clare that the following is a full, clear, andexact description of the invention, which will enable others skilled inthe art to which it appertains to make and use the same, reference beinghad to the accompanying drawings,and' to the letters of reference markedthereon,

In an application for a patent filed by me October 24,1S79,1 have shownand described certain improvements in electric signal apparatus fortelephones, in which all the circuitinstruments having singleground-connections are entirely controlled and operated by means of abattery and a transmitter at the central or main station and under thecontrol of the results eflected by such central-controlling sys term arethe making and unmaking of a single ground-connection of thecircuit-stations from the main office, and preventing the improper useof the ground-connections at the'stations by the subscribers. \Vhile insuch invention I efl'ect the control of the single ground-connectionsfrom the main office, I do not, however, make the communicationsprivate, and to this end my present improvements are directed.

My means of my present invention the operator at the main station andany one of the subscribers upon anyone line,when connected through withanother line, can hold private telupon such through line to theexclusion of all interference from the subscribers on either line. Ineffecting this object I employ a douorganization of devices for eachcircuit-instrument for controlling the ground-connections of each or allthe circuit-instruments at will from the main station. 7

Referring to the accompanying drawings, Figure 1 represents averticallongitudinal section of a circuit-instrument, showing itsauxiliary switch and double ground-connections,

ing the line-wire with the two ground-wires, 6o

detached and on an enlarged scale,thedouble ground-connections beingshown as broken; Fig. 5, a similar view, the double ground-connectionsbeing shown as made; Fig. 6, a detached sectional view ofa portion ofthe groundmaking lever on the line 0 0 of Fig. 8, showing its relationto the upper one of the lineconnecting levers, and Fig. 7 a detachedsectional view on the line z z of Fig. 8, showing the connection of thelower line-connecting lever with the ground-making contact-point, theconnected levers thereby making separate ground-connections; Fig. 8, apartial horizontal section, showing the relation of the tappetshaft tothe ground-making lever, the upper line-connecting lever, and theescapement; Fig. 9, enlarged sectional and bottom views of theescapement; and Fig. 10 is a diagram illustrating the connections of thecircuit-instruments, and showing a station, 6, on one line in privatecommunication with a station, 3, on another line, to the exclusion ofall others, the two lines being connected through at the main station.In this diagram is also shown a station, 4, between the two stations inprivate communication, switched in but cannot hear the privatecommunication. Fig. ll'shows the bell and push-button circuits and theirrelation with the switch, the coupled levers, and groundcircuits. j V 0In these several views the same letters indicate the same parts. j It isunderstood that the main station (indicated by E) isprovided with asuitable transmitter, batteries, and office appliances for con- 5necting and operating the different circuit-instruments, preferably suchas shown and described in my said application, and in which a sectionalbattery is'used, its sections having different degrees of power for-thepurposes mo therein stated. j I

The circuit-instrument is provided with a bell-operatingelect-ro-magnet, a, and an electro-magnet, b, for operating the armaturec, which, by its pivoted lever d, operates the escapement device carriedby said lever and re volves the tappetshaft c, which operates theground-making and line-connecting levers. The electro-magnets haveproper line-connections for operating the mechanisms of thecircuit-instruments.

The specific matter of my present invention is intimately connected withthe devices constitutingthe tappet-shaft and its driving mechanism, andbeyond this I do not, therefore, deem it necessary to particularlydescribe the circuit-instrument in all its details.

The tappet-shaft e is arranged in suitable hearings in the side platesof the frame, and between and below the magnets, as shown in thedrawings. The tappetf, Figs. 2 and 8, is for operating thecircuit-breaking lever f for shunting out the call-bell A, and thetappet g is for operating the circuit'breakin g lever g to shunt out thepush-button of the instrument, While the tappet g operates a unisonmechanism for bringing the tappet-shafts of all the circuit-instrumentsto the normal point. These operations are effected and controlled by thetransmitter and battery at the main station, and they form no part of mypresent invention. The bell and push-button circuits, however, are shownin Fig.1]. in their relation with my present invention, and thesecircuits I will now briefly trace and describe in connection with suchfigure.

The bell A is shown in circuit by the wires a a and it is shunted out bymeans of the wire a, the contact-pointf and the circuitbreakerf, whenthe latter is resting upon said contact-point. The push-button E is incircuit by means of the wires a a, and is shunted out by means of thewire a, the contact-point g and circuit-breaker y, when the latter isresting upon the contact-point g and the relative connections of thesecircuits, with myimproved call apparatus, can be readily traced throughthe switch, the coupled levers i t", and the ground-circuits, which arealso shown in the view referred to.

The leversf, g, and h are hinged upon a cross-shaft, D, Figs. 1 and 8,the ground-making lever it having a non-conducting bushing or hearing,I), on said shaft, by which the ground-wire 1 is kept insulated from thecircuit-breakers and apparatus, otherwise there would be a permanentground-connection. The lever h is connected to the telephone and then tothe ground by the wire 1, Figs. 1 and 8, and it is operated by thetappet h; and, by means of the spring-coupled levers or movable membersit, operated by the same means, both ends of the line are grounded atthe circuit-station without breaking the continuity of either section ofthe line, thereby establishing private communication to the mainstation, or through the main station to a circuit-station on anotherline, and this is a primary feature of my invention. I employ anadditional tappet,j, to operate these same levers hi t" simultaneouslyin each of the circuit-instruments for the purpose of makingground-connections for each of the instruments, whereby any twosubscribers on the same line can communicate with each other; and whilethis has been hitherto effected, yet the means by which I effect thisare new.

The tappet h is adjusted upon its shaft 0 differently at each station,so as to make the ground-connections successively at each station, andthis is the means for putting any par ticular station in privatecommunication with the main station or with a station upon another line.This successive connection is made by raising the lever h successivelyat each sta tion. For instance, the tappet h at station No. 1 isadjusted on the shaft 0 so as to raise said lever It after the shaft hasbeen moved forward one tooth of the escapement-wheel, while at stationNo. 2 the tappet h is adjusted on the shaft 0 so as to raise said leverafter the shaft has been moved forward two teeth, and so on throughoutall the circuit-instruments.

The tappets 7' are arranged in all the instruments so as to succeed intheir action that of the tappets h,- but, as before stated, their actionin all the instruments is simultaneous to effect the object beforestated.

The spring-coupled levers t 1" make the two ground-connections, thefirst being made by the top lever, z, and its metallic contact-point iwith the lever h, while the second of these ground-connectionsis made bythe lower lever, i, and a metallic insulated projection, i", andcontact-point i and from which metallic projection the secondground-connection is made by the wire 2. These levers i t" are hinged toa hard-rubber sill, It, and they are coupled by a spring, 1, Figs. 3, 4,and 5, by which the raising of the top lever by the action of the tappeth upon the lever h is caused to raise the lower lever, 'i', to make thesecond ground-connection through the contact-point 6, carried by saidlower lever. The lever It breaks its groundcontact with the top lever,i, by dropping of its own weight upon an insulated pin, 10, Fig. 6, andthus separating from the contact-point i, while the descent of the toplever, i, is arrested by a pin, m, Figs. 3, 4, and 5, on thenon-conducting sill. In the descent of the top lever, i, it makes acontact with a screw, 11, Figs. 3, 4, and 5, carried at the free end ofthe lower lever, for the purpose of bringing the levers into contactwith each other to connect both ends of the line, the spring I beinginsu lated from one of the levers, as shown at o in Figs. 3, 4, and 5.

The object of coupling the levers i i by means of a spring is to allowthe upper lever to have a slightly greater movement than the lowerlever, and cause the movements of the upper lever, t', to control themovements of the lower lever, 'i, in making and breaking theground-connections. The making and breakcontact with the projection iand then follows the breaking of the lever h with the le- -ment, andbefore they are released from their and 4, which are connected with thespringing of these connections are, however, not simultaneous, butfollow in quick succession. In their normal position, or position ofrest upon the pin m, these levers have their groundconnections broken,as shown in Fig. 4, and the line is closed through the screw-contactpoint a. The raising of the upper lever, t, by the lever It makes thefirst ground-connection, and in quick succession the secondgroundconnection is made by the screw i carried by the lower levertouching the projection 6 and immediately following this last contactthe contact between these levers is broken by the lifting of the upperlever from the screw-contact a, as shown in Fig. 5. In the downwardmovements of these levers they come in contact with each other first bythe screw n, and in quick succession the lowerlever releasesits ver 1The reason for making the contact between the coupled levers in theirdownward moveground-contact points, is to connect the two ends of theline before the ground-circuits are broken; otherwise the continuity ofthe line could not be preserved. v

In the drawings I have shown the making of the contact between thecoupled levers by a screw, it, carried by the lower lever; but it isobvious that such point may be carried by the upper lever with the sameresult. So, in like manner, the screw 1' may be carried by the lever hand the contact-screw i set in the projection i The device of thecoupled levers is perfect for the purpose designed; but I do not wish tobe contined to the specific construction and arrangement shown, as thesemay be changed and effect the desired results in controlling the twoground-connections.

The line-connections with the two groundconnections 1 and 2 are made bythe wires 3 coupled levers i i, as shown in Figs. 1, 3, 4, and 5, andwhich levers connect with an auxiliary switch of novel construction, andwhich I will now describe. This switch-insulated bed,'Fig. 1, is securedto any part of the circuit apparatus. It consists of a lever, (J,pivoted at one end bya screw,c and is arranged to be moved to the rightor to the left, and is in metallic connection with the top one, t, ofthe coupled levers by the wire 3. Arranged in line with each other,parallel to and ateach side ofsaid lever O, is secured a metallicspringplate, 19 19, which are in metallic connection witheach otherthrough the wire 5. Crossing the free ends of these springs are twoother me tallic spring-plates, q q, having their free ends overlappingthose ofthe under springs and constantly pressing thereon, holding themaway from their contact-points fip when the switchlever O is in itsnormal position or out of action, The distance between the ends of thespring-plates q q must be greater than the p, the wire 5 to thespring-plates 1) and q, through the wire 9 to the binding-post 10. Topermit the telephone to be connected with the main station, or with anystation between the main station and the communicator, the switchleveris turned to the lett, and the circuit is through the wire 8 to thespring-plates q and from the binding-post 6 to the spring-plate q, 4

the lever O, and thence by the wire 3 to the upper lever, 2', throughthe contact-point it of the lower lever, i, through the wire 4 to thecontact-points p and p thence through the spring-plate p, the wire 5, tothe springplates p and q, to the binding-post 10. In this'connection theswitch-lever lifts the spring-plate g from its pressure upon thespring-plate p, and allows the latter to rise against the contact-point19 thus making the connection to said post 10 and theline. Tocommunicate in the opposite direction from thatjust described, on thesame line, the switch-lever is turned to the light, making the circuitfrom the bindingpost 6, thejoining date-springs q and p, to thecontact-pointp, and thence through the wire 4 to the levers i and i bythe contact-point n, and from said lever 93 by the wire 3 to theswitch-lever O, and through the spring-plate q to the binding-post l0and the line. When the subscriber desires to have telephoniccommunication with the central station or anycircuit-station he turnsthe switch-leverO to the right or to the left to connect both sectionsof the line with the spriug coupled levers i t" of his instrument, andthereby completes the line through said levers. The central stationhaving been previously called by the call-bell, the main-stationoperator then makes the groundconnection at such station by the liftingof the lever h, (by operating the mechanism in the circuit-instrument bymeans of the battery and the apparatus at the main station,) therebyputting the spring-coupled leversi 2 in connection with the groundwires, and thus grounds both sections of the line, within one of whichgrouml-wires the telephone is included, and this is the means by which asubscriber is put in telephonic communication with the main station or acircuit-station, and hence it will be noticed that the subscriber canonly obtain telephonic communication at the will ot'thc op erator at themain station.

The peculiarities of the switch consist in the arrangement of thespring-plates and contactpoints in relation to the lever, whereby I notonly control the ground wires at the circuit stations fromthe mainstations, but make both ground-connections without breaking the continuity of either section of the line, and by which the switch isadapted for the specific use of mechanism for effecting privatecommunications.

The escapemeht consists of two toothed wheels, r 8, Fig. 9, on thetappet-shaft e, and having an equal number of teeth, into one, r, ofwhich engage two spring-pawls, r 1' carried by the oscillating lever d,and operating to rotate the tappet-shaft one-half of a tooth, either bythe forward or backward movement of said lever, the forward movementbeing effected by the attraction of the armature 0, and the backwardmovement by the retractingspring d, when the magnet is discharged. Thelever 11 has two detents, t t, which engage with the teeth of the wheel5- after each movement of the tappet-shaft and prevent it from mow ingeither forward or backward, and make a reliable escapement.

In the diagram is represented two lines, each having a number ofcircuit-stations located thereon, connected through the main station E,and each capable of effecting the double ground-connection. In thisdiagram the stations on each line are numbered from 1 to 10, and thelines are designated by the letters F and G, to illustrate how privatecommunications are had on one line to the main station, or to a stationon another line through the main station. At all the stations but thatnumbered 6 on line F and that numbered 3 on line G the swing-coupledlevers i '1' (indicated by H) are shown as having no groundconnections,the letter I representing the ground-making lever h, which is shown asbeing open, while in station No. 6 on line F, and in station No. 3 online Gr these levers h (indicated by J) are shown as being in contactwith the upper lever, 2 and the lower lever, i, as being in contact withthe metallic projection t, and in this way the double ground-connections1 and 2 are made, and thus these two stations 6 and 3 are put in privatecommunication, and to the exclusion of all interference from thesubscribers on either line. At these stations the switch -levers areshown as having switched in the telephones. it will be understood thatthis double groundconnection can only be made from the main station bymeans of the transmitter and battery operated there and at the requestof the communicator, oratthe will ofthe operator at the main station.

To illustrate how the privacy of communications between the two stationsdesignated above may be maintained without interruption, I have shown instation No. 4 on line F the switch lever as being moved in the positionto make telephone-communication by a subscriber intending to overhearthe communications which are passing between stations No. 6 and No. 3 onthe two lines; but as his telephone can have no connection with theline, for the reason that the connection between the ground-lever h andthe upper lever, i, is broken, as in all the other stations, exceptthose numbered 6 and 3, it follows that neither No. 4 nor any otherstation can interfere, and the movement of the lever at No. 4 or anyother station will be without effect.

The operation of the circuit-instruments is as follows, viz: Theoperator at the main station desiring to converse with the subscriber atstation No. 6, line F, be closes and opens the circuit six times. henthe circuit is closed for the sixth time the tappet h will beimmediately under the lever h, and when it is opened for the sixth timethe armature c is released from the magnet 11, the lever d is drawn backby the retracting-spring d, the spring-pawl r engages with the wheel 1'and moves the shaft 0 forward one point, which brings the tappet h incontact with the lever h, which is thereby thrown up,and makes contactwith the lever i at i and raises it, thereby connecting the telephonewith the switchlever (3. The lever 11, being held up by the spring I, isalso raised during the lifting ofthe lever t. and is brought in contactwith the insulated metallic projection 2 to which is attached thegroundwire 2. The subscriber now turns the lever C to the left, whichbrings it under the spring-plate q, raises it, and allows thespring-plate p to come in contact with the contact-point 11 During thisoperation of the lever O by the subscriber both ends of the line are putto earth at his station without breaking the continuity of eithersection of the line, one end of the line being put to earth at (1through lever 0, wire 3, lever 1', contact-point t lever h, throughtelephone T, and ground-wire 1. The circuit of the other end of the lineto the earth is from binding-post 10, wire 9, spring-plate q,spring-plate 19, wire 5, spring-plate p, contact-point 1)", wire 4,lever i, insulated metallic projection i and ground-wire 2. It will beseen that the telephone at station No. 6, line F, is the only one incont-act with the line, all others being disconnected at thecontactpoint i Station No. 6 can now communicate privately with theoperator at the main oflice; or, if the line is connected through toanother line similarly arranged,can communicate secretly with anothersubscriber upon such line, to the exclusion of all others. At the end ofthe conversation the operator at the main station restores allinstruments to their normal position, which is done by moving thetappet-shaft in all the instruments until the normal or zero point isreached. At the first movement of the shalt during this operation theground-connections at station No. 6 are broken and both ends of the lineconnected, thereby rc-establishing a circuit throughout the entire line.This is accomplished in the following manner: Suppose subscriber No. 6has his telephone switched to line, which really grounds the line at hisstation. The operator at the main station then puts his battery to line.The electro-maguet b is magnetized and attracts the armature c on thelever (1, thereby moving said lever d,

The tappet h is thereby moved from under the leverh, which drops,allowing the springcoupled levers i i. to make contact with each otherthrough the screw it, thereby connecting the two sections of the lineand breaking the contact with the lever h at 2' The lever z" is by thismeans caused to drop by its own weight, breaking its contact with theinsulated metallic projection 45 The levers it" are so adjusted as tomake contact with each other before the ground-connections are broken,so that there will be no break in the circuit. There is anothertappet,j, upon the shaft 0,

- adjusted alike in each instrument, so that the lever h is raisedsimultaneously in each instru-' ment. This arrangement becomes necessarywhen any .two subscribers upon the same line wish to communicate witheach other.

Theoperation of this mechanism is as follows: Suppose subscriber atstation No.2 desires to converse with subscriber at N o. 5. He calls themain-station operator, who answers by giving a blow upon the bell at No.2. The subscriber then switches his telephone to line by turning lever(J of the switch to the left, and notifies the operator at the mainstation to connect him with subscriber No. 5, and then turns the lever Gto the righ t, therebyconnecting his telephone to line out--that is,that part of the line running to station No. 5. The telephone at stationNo. 4 cannotbe embraced in the circuit with No. 5, because thegroundconnections, which are under the control of the main station, haveonly been made for station No. 5, to the exclusion of all other stationson the line, including No. 4. The main station then calls subscriber No.5 and tells him of the fact, and then movesthe shaft 0 in all theinstruments until the point is reached where the tappet j raises thelever h, and the two subscribers can now converse with each other. Atthe end of the communication station No. 2 turns the lever O to theleft, which switches his telephone to line iuthat is, that part of theline running to 'the main station-and tells the operator that he is donespeaking to No. 5. Themain-station operator then restores all theapparatus to the normal point by moving the shaft 0 forward one point.

It will be seen that the main station always has a circuit through anyapparatus on the line, no matter which way the ground-lever G is turned,and therefore has complete control over all the mechanism in eachinstrument,

and can operate them at will and place all subscribers beyond the powerof interfering with the line, either by accident or design.

The number of stations on the lineis limited to two less than the numberof teeth in the wheel 1. For instance, the wheel in this iiistrument hastwelve teeth. The number of stations is therefore limited to ten, thefirst ten teeth being to give each of the ten stations separate groundconnections, the eleventh .tooth is to give all of the ten stationssimultaneous ground-connections, .and the twelfth tooth is the normalpoint.

Any number of subscribers may be placed on one line by increasing thenumber of teeth in the escapement-wheels.

I claim- 1. In switches for telephone-lines, the combination of a groundcontrolling device for the circuit-instrument, consisting of two coupledlevers, i i, or movable coupled members, through which the line is madeand broken through a contact-making screw, it, carried by one of saidcoupled members, with a groundmaking lever, h, operating with one ofsaid coupled members, and an insulated groundcontact-making projection,i operating with the other of said coupled members, the said movablemembers being connected with the line, whereby, in the upwardmovementofthese coupled members both ends of the line are put to groundat the circuit-station directly and exclusively from the main station,and without breaking the continuity of either section of the line, thedownward movement of said coupled members operating to join thesect-ions of the line and to break the ground-coni'iections there of,for the purposes specified.

2. The combination, in a, switch for telephone-lines, of a groundcontrolling device consisting of coupled levers or movable coupledmembers, through which the line is made and broken, substantially asspecified, with a ground-contactmaking lever, 71, and operating-tappet htherefor, a fixed ground-making insulated projection, 01 operating withone of said coupled levers and the driving mechanism for said tappet,whereby private telephonic communications are established with the mainstation, or with another station on another line through the mainstation, the said tappetbeing adjusted to operate upon the ground-makofsaid coupled levers, and the driving mech-- anism for said tappet,whereby the groundmaking lever h of each station is raisedsimultaneously to allow telephonic communications to be made between anytwo stations on the same line, substantially as specified.

4.. The ground-making lever h, operated by the tappets h and j, theaction of one succeeding that of the other, in combination with theground-controlling coupled levers i i, substantially as and for thepurposes herein specified.

5. The combination, in a telephone-call apparatus, of the ground-makinglever h, and the circuitbreakers f and g, with the hard-rubber bushing Dupon the shaft D, upon which bushing said lever h is mounted, wherebythe linewvires connecting with said circuit-breakera are prevented frombeing permanently ing a double grouiul-connection, for the purpose setforth.

8. The ground controlling spring-coupled levers i 5, limited in theirdescent by the stop m, for maintaining them in position for the properoperation of the ground-makin g lever h, as specified.

9. The combination, in a telephone-call apparatus, of the tappet h, theground-making lever h, operated thereby, the spring-coupled levers i i,and the contact-point i with their line and ground connections 1, 2, 3,and 4, the said tappet h being adjusted upon its shaft 0 difi'erently ateach circuit-station, and making the ground connections successively ateach circnit-station, whereby to put any particular circuit-station inprivate telephonic communication with the main station or with acircuitstation upon another line, substantially as set forth.

10. The combination, in a telephone'call apparatus, of thespring-coupled levers i i, the insulated projection '5 the stop m, andthe contact-points n, 6 and i with the ground-making lever h, wherebythe contact between the coupled levers in their downward movements ismade before they are released from their ground contact-points, for thepurpose of connecting the two ends of the line before theground-circuits are broken,to preserve the continuity of the line. 7

11. The auxiliary switch consisting of the lever O, the spring-plates pp q q, and the contactpoints p 1;,in combination with theirconnecting-wires 3, 4, and 5 and the lineconnections 8 and 9, wherebydouble ground-connections are effected without breaking the continuityof the line, substantially as specified.

12. The combination of the auxiliary switch, constructed substantiallyas specified, with the ground eontrollin g coupled levers i i, theground-making lever IL, mechanisms for operating said levers, and theirconnecting wires, substantially as and for the purpose specified.

In testimony that I claim the foregoing I have hereto afiixed mysignature in the presence of two witnesses.

ANTHONY M. FRANKEUBERG.

Witnesses:

O. H. SLIOER, A. E. H. JoI-INsoN.

